How to draw circle on the MAP using GMAP.NET in C#

Question

I am using GMAP.NET in c#. I am able to display the map on the form, now i am trying to draw a CIRCLE mouse by clicking on a certian point, keeping the left mouse button and dragging the mouse upto specific place. Once the circle is drawn I want to get its radius in miles from the center point which I am sure GMAP is capable of doing it. I am using Opentstreet maps.

I am just unable to achive this functionly, anybody who has played with GMAP control kindly share your experience with some code which will work.

Thanks

Answer 1

The only way that I am aware of that can achieve such a result is to create a list with PointLatLng points and draw them as a polygon. Here is an example:

private void CreateCircle(PointF point, double radius, int segments)
{

    List<PointLatLng> gpollist = new List<PointLatLng>();

    double seg = Math.PI * 2 / segments;

    for (int i = 0; i < segments; i++)
    {
        double theta = seg * i;
        double a = point.X + Math.Cos(theta) * radius;
        double b = point.Y + Math.Sin(theta) * radius;
    
        PointLatLng gpoi = new PointLatLng(a,b);

        gpollist.Add(gpoi);
     }
     GMapPolygon gpol = new GMapPolygon(gpollist, "pol");

     overlayOne.Polygons.Add(gpol);
 }